1. Field Of The Invention
This invention relates to agricultural chemical (agrochemical) compositions containing specific film-forming resins. More specifically, it relates to agrochemical compositions which have the improved efficiency, long range effectiveness and decreased phytotoxicity to useful plants, and methods of imparting the above properties to agrochemicals.
2. Description Of Prior Art
Recently, various agrochemicals have come into wide use to simplify various aspects of farm work, e.g., labor saving materials, and the use of these chemicals has contributed much to increased crop yields. However, the conventional methods of using agrochemicals have the disadvantage that the agrochemicals must be applied to plants or to soils in large amounts and high frequency in order to obtain good results, because, in a rather short time, the chemical agents may be washed by rain into the subsoil, degraded by bacteria in the soil, or escape in vapor, resulting in reduced effectiveness of the agrochemicals. In addition, some herbicides tend to be so easily eluted with water from the upper soil into the subsoil that they are rendered ineffective and that, sometimes, they adversely affect germination or growth of useful plants, or cause withering of useful plants which usually have their roots in the subsoil.
On the other hand, the hazard due to excessive use of agrochemicals has been a major problem of society in view of increased understanding of environmental problems. Therefore, the improvement of the above-mentioned drawbacks has been expected.
To improve these disadvantages, heretofore, spreaders (e.g., nonionic and anionic surfactants) have been incorporated in agrochemical compositions, but they are unsatisfactory for preventing agrochemicals from leaching by water and escaping in vapor. Other methods have been proposed to overcome the above disadvantages in which methods agrochemicals are coated with a resin, or they are formulated with a resin, or, at the time of their application, they are mixed with a resin. Some examples of the resin are polyvinyl chloride, polyethylene, polystyrene, polyacrylates, polyvinyl acetate and epoxy resins. These methods are insufficient to overcome the above disadvantages, and, furthermore, some are effective only for some limited agrochemicals, and others are difficult to apply, e.g., too high a viscosity, or too short in handling time to apply by a conventional sprayer.